Not for cosmetic purposes AFAIK
Only for problems affecting breathing, back pain, etc. (at least for procedures covered by govt, healthcare).
The medical standard of care in Canada requires the individual be an adult and undergo two years of gender affirming care and counselling (which can start as a minor) before undergoing permanent gender affirming/reassignment surgery, all covered by MSP.
As a retired Counsellor, that makes sense to me to delay surgery until adulthood while supporting and preparing the individual for the life altering impact the comes from surgery. (I had a client who was definitely a “Q” - Questioning- in their gender identity, and although not seeking surgery, was subject to mood swings and impulsive behaviour) This two year timeline would also help confirm gender dysphoric disorder was the issue being treated, and not another problem such as bipolar disorder, psychosis- both of which often emerge in late adolescence /early adulthood- or other problem where surgery would not be the appropriate treatment.
Edit to clarify: non-surgical, gender affirming care is available at any age in Canada, although most counselling is not covered under MSP.